1. Field
The invention is in the field of couplings to connect plain end or grooved end or shouldered end portions of pipes and pipe fittings.
2. State of the Art
There are various types of mechanical couplings which employ various radial mechanical means, such as clamps and split rings to secure the couplings to plain end pipes and pipes having circumferential grooves on the ends of the pipes and to connect the pipes to other pipes or to various pipe fittings. However, these couplings can develop leaks under excessive temperature changes when the pipe shrinks to assume a smaller diameter than the original diameter. For example, if the coupling is made of metal and the pipe is made of polyethylene material, the thermal differential expansion of the two materials is such that the developing of a leak is a natural outcome. To eliminate this problem, the coupling of the invention is provided with slidable jaw members which respond to the thermal diametrical change of the pipe, and with a diaphragm seal also designed to accommodate such changes. The coupling of the invention can accommodate predetermined thermal expansion of the pipe links, which other couplings cannot do.